Create a LIVE playlist from a specific starttime in another LIVE playlist

Preconditions

These scripts are based on the assumption that all HLS manifest files
and segments are archived at the origin server where these scripts are
executed. The archive for a specific live stream contains the history
for all HLS manifest updates. For example:

Live HLS stream called ‘foo’ is archived in the directory /archive/foo
on the server. It contains all updated HLS manifest files with a unix
timestamp when it was last updated.